separated lists. If an answer does not exist, enter DNE.$)$

$-9(x,y)=(0,0),(0,\frac{}{2}),(\frac{}{2},0),(\frac{}{2},0),(-\frac{}{2},0)f(x,y)=9sin(x)sin(y),-$

local maximum value$(s)$

local minimum value$(s)$

$-9$

saddle point$(s)$

$(x,y)=(0,0),(0,\frac{}{2}),(\frac{}{2},0),(\frac{}{2},0),(-\frac{}{2},0)$